Masahisa Matsunaga

Investigation of Vapor Adsorption on Molybdenum Disulfide Surfaces by Auger Electron Spectroscopy

The adsorption characteristics of the cleavage and edge surfaces of MoS2 were studied by Auger electron spectroscopy, and the following conclusions were obtained. The cleavage surface of MoS2 has difficulty in adsorbing the vapors, and the adsorbed vapor is easily evaporated from the surface in vacuum. On the contrary, the edge surface of MoS2 adsorbs vapors easily, and is difficult to evaporate. These experimental results could explain the difference in the frictional behaviors of cleavage and edge surfaces of MoS2. Sulfur is usually richer than the estimated stoichiometric value on the MoS2 surface, and even on the adsorbed surface. Ion etching can reduce the sulfur contents to the stoichiometric value. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in New Orleans, Louisiana, October 5–7, 1981

Friction and wear of sintered cast iron products

Abstract The wear and frictional characteristics of five types of sintered cast iron swarf powder, or the same powder decarbonized by a mechanical procedure, were investigated using a pin-and-disk-type apparatus. The contact pressure was 19.6 N cm−2 and the sliding velocity varied from 0.1 to 4.0 m s−1. The wear rate exhibited a maximum at a velocity of 1.0 m s−1. A slight improvement was found in specimens which were decarbonized and forged before sintering. However, the wear rate at lower velocities of these specimens was inferior to that of a specimen containing 5% graphite. The wear mechanism was investigated by scanning electron microscopy and electron probe X-ray microanalysis, and it was found that oxidation wear had an important effect.

Preparation and physical properties of (Bi1−xLnx)2.2Sr1.8CaCu2Oy (Ln=La, Pr and Nd, x≤0.25)

Solid solutions (Bi1-xLnx)2.2Sr1.8CaCu2Oy(Ln=La, Pr and Nd, x0.25) were prepared. Of these three Ln ions replacing Bi3+, Pr was not trivalent, the average valence of Pr being shown to be 3.5. With increase of x, the onset of superconducting transition temperature and hole concentration initially increase, then decrease steadily with increase of x equally for all the three series, irrespective of difference in lanthanide elements substituted.

Wear and frictional behaviour of MoS2 pellets and steel lubricated with MoS2 powder

Abstract The wear and frictional behaviour of compressed pellets of molybdenum disulphide (MoS 2 ) were measured when the pellets were slid against a 0.45% C steel disk in air. The wear of the MoS 2 pellets decreased with increasing sliding velocity and increasing contact pressure. These factors are indicated by a parameter μPV which corresponds to the frictional heat. A thin deformed surface layer on the sliding surface of an MoS 2 pellet was different from the MoS 2 substrate. The wear of a bearing steel slider against mild steel was reduced by an MoS 2 film in air and in vacuum. The specific wear rate of the slider and the coefficient of friction were influenced by the degree of vacuum.

The Wear and Friction Behavior of Molybdenum Disulfide Compacts

The wear and friction behavior of compressed compacts of molybdenum disulfide was examined during sliding in air against a 0.45 percent carbon steel disk. The contact pressure was 0.082 through 0.412 MPa, and the sliding speed was 0.03 through 5.00 m/s. The specific wear rate (wear volume per unit sliding distance/load) under various experimental conditions was found to be a simple function of a parameter fPV, corresponding to the frictional heat. It was noted with interest that the wear of molybdenum disulfide compacts decreased when sliding conditions were made more severe. Presented as an American Society of Lubrication Engineers paper at the ASLEIASME Lubrication Conference In New Orleans, Loulsiana, October 5–7, 1981

Expert Computer System for Barrel Finishing.

This paper treats the expert computer system for selecting barrel finishing operations. The barrel finishing data concerning the barrel machines, the features of workpieces and the finishing conditions, such as the selecting of media and compounds are classified to construct the expert system on the rule base and frame base learning system. The expert system composed of both production system and frame system is developed. The production system of two stages is introduced in the system. The preferable barrel machines can be selected by the first stage system, and the preferable finishing conditions, such as, the selection of media and compounds are decided by the second system. The combination of more than two barrel finishing conditions can be also decided by the system. It is found that the preferable barrel finishing conditions can be obtained by using the expert computer system which is developed in the study, and the verification results coincide fairly well with the experimental results.

Studies on TiN-Fe binary sputtering.

Multicomponent films of TiN and Fe with various composition ratios (TiN/Fe=x/y (vol)) were deposited on steel substrates by RI sputtering using a single generator, the power from which was split by variable coupling capacitors and applided to TiN and Fe targets. Hard multicomponent films of TiN and Fe were made to improve adhesion to the steel substrate.The adhesion of films on the steel substrates was measured by a scratch tester.Specimens with a series of TiN/Fe ratios (0/10, 2/8, 4/6, 6/4, 8/2, 10/0) were obtained by changing voltage under a constant argon-plus-nitrogen pressure of 1.3Pa.Film composition was measured by x-ray diffraction and EPMA.The results show that multicomponent TiN/Fe films were homogeneous, and adhesion to the steel substrates was the same that of single-component TiN films.

Measurements of oxide film thicknesses on the worked surfaces of silicon and aluminum by Auger electron spectroscopy.

It has been reported, that the thickness of oxides on Si or Al can be determined up to about 120A, using Auger electron spectroscopy, without ion-milling depth profiling, by using the ratio of the chemically shifted and unshifted peaks from the oxide asd the substrate, respectively. These measurements can be difficult, however, when the resolution of the apparatus is insufficient. Calculation of the ratio by a micro-computer was carried out, and very good coincidence was obtained between the experimental and composed spectra. Film thicknesses are obtained more accurately by using the present method.

Frictional Behavior of Molybdenum Bisulfide in High Vacuum

The coefficient of friction and stop time effect of molybdenum disulfide in high vacuum were investigated. It was found that three kinds of stop time effect existed. In explaining the variation of coefficient of friction during run-in after various period of standing, diffused vapor concentration under the surface was considered and the variation of coefficient of friction was determined by a solution of Ficks law. It was found that the experimental results coincided with the theory.

Examination of Plating on ABS Plastics and Its Adhesion under Electron Microscope

This paper reports the research on adhesion mechanism of electroless plating on ABS plastics under an electron microscope. Peeling test was conducted to determine the adhesive strength between copper and the plastics. It was indicated in normal plating conditions that peeling did not occur on the interface between plastics and metal, but on the surface layer of the plastics; and the adhesive strength depended upon the strength of the surface layer of the plastics. Hence, the molding and etching conditions of plastics had powerful effects on the adhesive strength. The above effects would be caused by the presence of internal stress and orientation in the contact part with the mold which made that layer concentrically brittle. The presence of such layer was observed under the electron microscope. The etching conditions had effects on the formation of dovetail joints. Stronger adhesion was produced by the formation of numerous joints under proper etching conditions. However, the parts of anchoring were limited on the whole, and chemical combination would also be taken into consideration for adhesion mechanism.